fix: Fix signal test failures in Django 5.2. (#37193)

Author: awais786

common/test/utils.py

@@ -85,11 +85,14 @@ def assert_signal_sent(self, module, signal, *args, **kwargs):
 
         """
         with patch.object(module, signal, new=Signal()) as mock_signal:
-            def handler(*args, **kwargs):  # pylint: disable=unused-argument
+            mock_handler = Mock()
+            # Wrap the mock in a real callable so inspect.iscoroutinefunction() works
+
+            def handler(*h_args, **h_kwargs):
                 """No-op signal handler."""
-                pass  # lint-amnesty, pylint: disable=unnecessary-pass
-            mock_handler = Mock(spec=handler)
-            mock_signal.connect(mock_handler)
+                return mock_handler(*h_args, **h_kwargs)
+
+            mock_signal.connect(handler)
             yield
             assert mock_handler.called
             mock_args, mock_kwargs = mock_handler.call_args